Three months of the child has been coughing for the following reasons: First, the medication is unreasonable: the child cough symptoms, parents to give the child to take the drug is not symptomatic, or see the child’s cough symptoms to reduce the child to stop taking medication, resulting in the child’s coughing symptoms have always existed. It is recommended that parents take their children to the hospital to check the blood routine or do blood culture, according to the results of the doctor’s orders to give symptomatic antiviral, antibacterial drug therapy, the dose and course of treatment must be in accordance with the doctor’s orders, in order to ensure the safety and effectiveness of the treatment. Second, allergic cough: the child is allergic, the environment in which there are substances that can cause allergies in children, allergy-induced cough taking antibiotics or cough suppressant medication is not effective, resulting in the phenomenon of the child has been coughing. Parents are advised to take their children to the hospital to test for allergens, and to stay away from allergens so that the coughing symptoms will slowly disappear.